In an image forming apparatus, such as a laser printer or a copying machine, a process cartridge which is attachable to and detachable from a main body of the image forming apparatus (hereinafter, referred to as an “apparatus main body”) is provided.
The process cartridge is a member which forms content to be expressed, such as letters or figures and transfers the content to a recording medium, such as a paper sheet. More specifically, the process cartridge includes a photoreceptor drum, and, the content to be transferred is formed on the photoreceptor drum. In addition, in the process cartridge, various means for forming the content to be transferred to the photoreceptor drum are also disposed. Examples of these means include a developing roller unit, a charging roller unit, and means for performing cleaning.
In regard to the process cartridge, the same process cartridge is attached to and detached from the apparatus main body in maintenance, or a new process cartridge is mounted on the apparatus main body after an old process cartridge is disengaged from the apparatus main body. The attachment and detachment of the process cartridge can be performed by users of the image forming apparatus manually, and thus, it is desirable that the attachment and detachment can be easily performed as much as possible.
However, a driving shaft of the apparatus main body is engaged with the photoreceptor drum which is included in the process cartridge directly or via another member, and according to this, the photoreceptor drum receives a rotating force from the driving shaft and rotates. An end member which receives the rotating force from the driving shaft and transmits the rotating force to the photoreceptor drum is disposed in an end portion of the photoreceptor drum. Therefore, in order to attach and detach the process cartridge to and from the apparatus main body, it is necessary to release (disengage) the engagement between the driving shaft of the apparatus main body and the end member, and to reengage (mount) the process cartridge for every attachment and detachment.
Here, if it is possible to move the photoreceptor drum (process cartridge) in a direction along an axis of the driving shaft of the apparatus main body, and to attach and detach the photoreceptor drum to and from the driving shaft, an apparatus configuration for the attachment and detachment is relatively simple. However, from the viewpoint of reducing the size of the image forming apparatus and ensuring space for the attachment and detachment of the process cartridge, it is preferable that the process cartridge is disengaged from the apparatus main body by pulling out the process cartridge in a direction which is different from the direction along the axis of the driving shaft, and that the process cartridge is mounted on the apparatus main body by pushing the process cartridge in a direction opposite to this.
In PTL 1, a configuration for attaching and detaching a process cartridge in a direction which is different from a direction along an axis of a driving shaft of an apparatus main body is disclosed. Specifically, a coupling member (shaft member) which is disclosed in PTL 1 and is provided in an end member is swingably attached to a drum flange (bearing member) with a spherical portion provided therein. Therefore, a part (rotating force receiving member) which is provided in the coupling member (shaft member) and is engaged with the driving shaft of the apparatus main body can swing around the spherical portion to change an angle with respect to the axis of the photoreceptor drum, and mounting and disengagement between the driving shaft of the apparatus main body and the photoreceptor drum become easier.
In addition, NPL 1 discloses a structure in which a groove for introducing a rotating force transmission pin provided in a shaft member in an end member into a bearing member, is provided in an inner circumference of the bearing member along a rotational direction, and the groove facilitates the attaching of the rotating force transmission pin to the bearing member.
In NPL 2, a cruciform member (intermediate member) which links a coupling member (shaft member) to an end member (bearing member main body) such that the coupling member becomes swingable, is disclosed. Accordingly, the coupling member (shaft member) can freely swing with respect to an axis of the end member (bearing member main body).
In NPL 2, a coupling (shaft member) which is formed in a substantially tubular shape and links a driving shaft and a driven shaft, is disclosed. A part to be engaged with a pin of the driving shaft and a part to be engaged with a pin of the driven shaft, are provided in the coupling (shaft member), and a rotating force is transmitted with each pin being engaged with the coupling (shaft member).